Probing anomalous right-handed top quark couplings in rare B decays

We explore the anomalous right-handed $\bar{t}sW$ and $\bar{t}bW$ couplings using $B\to X_s\gamma$ and $B\to X_s{l}^{+}{l}^{-}$ decays induced by the flavour-changing penguin diagrams. The anomalous $\bar{t}sW$ coupling can yield 10% enhancement of the $B\to X_s{l}^{+}{l}^{-}$ decay rate under the constraint from the present $B\to X_s\gamma$ data, while it does not affect the forward-backward asymmetry of the charged lepton. The allowed region for anomalous $\bar{t}bW$ coupling by the $B\to X_s\gamma$ constraint is two-fold, the small value region and the large value region. Though the effect of the small anomalous coupling on the $B\to X_s{l}^{+}{l}^{-}$ branching ratio is very little, it can yield a substantial chanhge for the forward-backward asymmetry.